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Bureau of Mines Information Circular/1987 




Performance Evaluation of Two 
Light-Scattering Dust Monitors 

By R. P. Vinson and K. L. Williams 




UNITED STATES DEPARTMENT OF THE INTERIOR 




Information Circular/9162 

Performance Evaluation of Two 
Light-Scattering Dust Monitors 

By R. P. Vinson and K. L. Williams 



UNITED STATES DEPARTMENT OF THE INTERIOR 
Donald Paul Hodel, Secretary 

BUREAU OF MINES 

David S. Brown, Acting Director 



Library of Congress Cataloging in Publication Data: 



\\z°& 






\& 



Vinson, Robert P. 

Performance evaluation of two light-scattering dust monitors. 

(Information circular ; 9162) 

Bibliography: p. 9 -10. 

Supt. of Docs, no.: I 28:27: 9162. 

1. Mine dusts -Measurement -Instruments. I. Williams, Kenneth L., 1952- II. Title. 

III. Series: Information circular (United States. Bureau of Mines) ; 9162. 



TN295.U4 



[TN312] 



622 s 



[622'.8] 



87-600188 



CONTENTS 



Page 



Abstract 1 

Introduction 2 

Test equipment and procedures 2 

PDS-1 and PCD-1 dust monitors 2 

Aerosol chamber 5 

Reference measurements 5 

Other dust measurements 6 

Results and discussion 7 

Reference measurements 7 

PDS-1 response 7 

PCD-1 response 8 

Effect of particle size distributions 9 

Conclusions 9 

References 9 

Appendix A. — Manufacturer specifications 11 

Appendix B. — Total dust concentrations 12 

Appendix C. — PDS-1 and PCD-1 test data 13 

ILLUSTRATIONS 

1. PDS-1 Personal Dust Sensor and MDM-1 Mini Dosimeter 3 

2. MDM-1 and portable computer 4 

3. PCD-1 digital dust indicator 4 

4. Aerosol chamber, sectional top view 7 

5. PDS-1 readings versus gravimetric concentrations for coal dust 8 

6. PDS-1 readings versus gravimetric concentrations for ARD and coal dust... 8 

7. PCD-1 readings versus gravimetric dust concentrations for ARD and coal 

dust 9 

TABLES 

1. Reference respirable dust concentrations 6 

2. Ratios of total dust concentrations to reference respirable dust 

concentrations 7 

B-l. Total dust concentrations 12 





UNIT OF MEASURE 


ABBREVIATIONS 


USED 


IN THIS REPORT 


ft 


foot 


mg/m 3 


milligram per cubic meter 


h 


hour 


min 




minute 


in 


inch 


mm 




millimeter 


lb 


pound 


ym 




micrometer 


L/min 


liter per 
minute 


mV 
oz 




millivolt 
ounce 


m 3 /mln 


cubic meter per 










minute 


pet 




percent 


mg 


milligram 


s 




second 



PERFORMANCE EVALUATION OF TWO LIGHT-SCATTERING 

DUST MONITORS 

By R. P. Vinson 1 and K. L. Williams 2 



ABSTRACT 

The Bureau of Mines evaluated two real-time light-scattering dust 
monitors by measuring their response to Pittsburgh Seam coal dust and 
Arizona road dust (ARD). Both monitors, the model PDS-1, a personal 
dust sensor, and the model PCD-1, a digital dust indicator, are made in 
Japan by Sibata Scientific Ltd. Tests were conducted inside a labora- 
tory aerosol chamber designed to maintain a uniform spatial distribution 
of the test dust. PDS-1 and PCD-1 measurements of concentrations for 
each test dust were averaged over 4-h test periods and compared with 
simultaneous gravimetric measurements. 

Both dust monitors responded linearly with mass concentration with 
both coal dust and ARD. However, the linear response of the PDS-1 dif- 
fered from that of the PCD-1 for both dusts. 



1 

9 

Supervisory physical scientist. 



Physicist. 

Supervisor; 

Pittsburgh Research Center, Bureau of Mines, Pittsburgh, PA. 



INTRODUCTION 



One of the primary objectives of the 
Bureau of Mines is the elimination of 
coal miners' pneumoconiosis ("black 
lung") by reducing exposure to harmful 
dusts. Dust monitoring is critical to 
reducing respirable dust levels in mines. 
Most of the dust sampling in U.S. coal 
mines is done to determine compliance 
with dust standards. Measurements to 
determine compliance are made periodi- 
cally, usually every two months, with an 
approved sampler. Federal regulations 
(1_) 3 require gravimetric dust samples to 
be taken over an 8-h work shift. With 
gravimetric samplers, respirable dust 
particles are physically collected during 
the work shift and later weighed at a 
remote location. Since determination of 
compliance is based on the average of 
several shift-long measurements, the 
delayed analysis inherent in gravimetric 
techniques poses no problem. Further- 
more, since the standard is based on a 
2mg/m 3 mass concentration, the gravi- 
metric approach is quite suitable. When 
operated carefully, these samplers can 
provide an accurate measurement of the 
average mass concentration of dust to 
which miners are exposed. 

Although gravimetric samplers (commonly 
called personal samplers) have been used 
for other than compliance purposes, they 
are often too slow and labor intensive 
for effective research or immediate dust 



control purposes. In an earlier Bureau 
study, it was found that a fast-response 
instrument is more effective for evaluat- 
ing dust control systems ( 2) . Timely 
adjustment of dust control system operat- 
ing parameters requires more immediate 
dust level information than is possible 
with the gravimetric sampler. 

Light-scattering techniques have made 
possible rapid, real-time measurements of 
dust concentrations. The Bureau has 
played an important role in developing 
real-time dust monitors. For example, in 
recent years the Bureau sponsored the 
development of two light-scattering real- 
time dust monitors, the RAM-1 (3) and the 
MINIRAM (4_). 

Many other light-scattering dust moni- 
tors are commercially available. The 
University of Minnesota evaluated several 
of these instruments for the Bureau in 
1983 (_5). Two light-scattering instru- 
ments that were not available at the time 
of that evaluation have since been evalu- 
ated by the Bureau. The evaluation of 
these two monitors, the model PDS-1 per- 
sonal dust sensor and the model PCD-1 
digital dust indicator, is the subject of 
this report. The report discusses the 
ability of these instruments to measure 
mass concentrations of Pittsburgh Seam 
coal dust and ARD. 4 No attempt has been 
made to assess the mine-worthiness of 
these instruments. 



TEST EQUIPMENT AND PROCEDURES 



THE PDS-1 AND PCD-1 DUST MONITORS 

The PDS-1 Personal Dust Monitoring 
System has three major components: The 
PDS-1 Personal Dust Sensor, the MDM-1 
Minidosimeter, and a portable computer 
(Manufacturer specifications are listed 
in appendix A). 

The PDS-1 (fig. 1) is a portable, 
battery-powered, light-scattering dust 
detector. Dust particles diffuse into 



the PDS-1 sensing chamber, which contains 
a light source and detector. The detec- 
tor senses light scattered by particles 
passing through the light beam. The 
detected light is converted into an 
electric analog signal, which may be used 
to activate an audible alarm in the PDS-1 
if the signal exceeds a preset level. 
The PDS-1 incorporates a reference light- 
scattering board which is a translucent 
material that scatters a portion of the 



Underlined numbers in parentheses re- 
fer to items in the list of references 
preceding the appendixes. 



4 ARD is a carefully sized, commercial 
test dust used primarily to test the 
efficiency of air filters for internal 
combustion engines. 




FIGURE 1.— PDS-1 Personal Dust Sensor and MDM-1 Mini Dosimeter. 



light beam. Each time the board is in- 
serted into . the light beam, the same 
amount of light is scattered to the de- 
tector. The gain of the instrument can 
then be adjusted to indicate some arbi- 
trary value. The manufacturer calibrates 
the instrument to directly indicate the 
mass concentration for ARD. By inserting 
the reference board and noting the 
instrument reading, the manufacturer de- 
termines the numerical value that should 
be indicated whenever the board is in- 
serted in the future. The predetermined 
reference value is supplied with each 
unit. 

The analog signal from the PDS-1 can 
also be sent to the MDM-1 Mini Dosimeter 
(fig. 1), which is a battery-powered data 
acquisition system capable of storing 800 
1-min dust concentration averages. A 
digital display on the MDM-1 is contin- 
uously updated to indicate the current 



dust concentration. Data stored in the 
MDM-1 can be retrieved by a small por- 
table computer (fig. 2) that is program- 
med to do elementary statistical analyses 
on the dust sampling data. Three PDS-ls 
were made available and used for this 
evaluation. This improved the statisti- 
cal validity of the test data. 

The PCD-1 digital dust indicator (fig. 
3; specifications in appendix A) is a 
battery-powered, light-scattering dust 
monitor with a built-in air pump and 
microprocessor. Dust-laden air is drawn 
into the PCD-1 sensing chamber where, as 
in the PDS-1, dust is detected by light- 
scattering techniques. The microproces- 
sor contains user-friendly, menu-driven 
software that gives the PCD-1 great 
versatility. A keypad on the top of the 
PCD-1 allows the operator to program the 
PCD-1. In operation, the PCD-1 aver- 
ages the signal for a preset averaging 



interval and then stores that value in 
memory. The averaging interval can be 
adjusted from 6 s to 10 h> A maximum of 
6,200 6-s averages can be stored in mem- 
ory. The total sampling time may also be 



programmed, in 1-min increments, for up 
to 620 min. Because the response of 
light-scattering dust monitors often de- 
pends on the properties of the dust being 
measured, a calibration factor (called 






FIGURE 2.— MDM-1 and portable computer. 




FIGURE 3.— PCD-1 digital dust indicator. 



the "K Factor") may be entered into the 
microprocessor so that the true mass con- 
centrations are displayed and stored in 
memory. The PCD-1 also features a RS232C 
port, which is a digital interface, used 
for communicating with other computers. 

AEROSOL CHAMBER 

All tests were conducted in an aerosol 
chamber designed specifically for evalu- 
ating dust sampling instrumentation. The 
chamber is similar to the one used by the 
University of Minnesota to evaluate the 
other light-scattering dust monitors (5- 
6_). (See the introduction to this re- 
port.) The hexagonal 8-ft-high chamber 
is supported by a 2-ft high triangular 
base. Dust-laden air, produced by the 
dust generating system, passes through a 
krypton-85 5 particle-charge neutralizer 
and enters the top of the chamber through 
a 1-5/8-in-diam pipe. At the top center 
of the chamber, the dust-laden air first 
strikes a special target that evenly dis- 
perses it, then passes it through a 
honeycomb flow straightener designed to 
minimize turbulence. Drawn by a blower 
at the base of the chamber, the dust- 
laden air then passes the sampling in- 
strumentation, which is located on a 
round, rotatable table near the base of 
the chamber. The air finally passes 
through a perforated metal instrument 
table and is collected by a large, highly 
efficient filter located just above the 
blower. 

The aerosol chamber's dust generation 
system consists of a f luidized-bed aero- 
sol generator and a dilution-air system. 
The f luidized-bed aerosol generator can 
disperse dry powders with particle sizes 
from 0.1 to 20-ym-diam. Air blown 
through the bottom of a small cylinder 
containing bronze beads produces a fluid- 
ized bed. A loop of continuous ball 

c — — 

Krypton-85 gas, sealed in a small 

tube, emits beta and gamma radiation to 
ionize air molecules in a larger con- 
centric tube through which the gener- 
ated dust must pass. Charged particles 
passing through the ionized air sur- 
render much of their charge to the 
ionized air molecules. 



chain carries the dust from a reservoir 
into the fluidized bed of bronze beads. 
The motion of the beads breaks apart any 
dust particle agglomerates. Air blown 
through the bed then carries the dust 
particles out of the fluidized bed to the 
aerosol chamber. 

The amount of dust introduced into the 
chamber can be varied by changing the 
chain speed or airflow rate through the 
bed of bronze beads. Changing these 
parameters, however, can change the par- 
ticle size distribution of the dust that 
enters the chamber. Since the response 
of a light-scattering instrument is often 
affected by changes in particle size dis- 
tribution, random changes could introduce 
error into the determination of instru- 
ment response. Thus, whenever possible, 
an adjustable diluter was used to vary 
dust concentrations in the chamber with- 
out changing the dust generator operating 
parameters. First, the generator was 
allowed to stabilize at a high dust gen- 
eration rate. A diluter system was then 
used to divert a selectable portion of 
the dust-laden air, filter the dust par- 
ticles from that portion, and return the 
filtered air downstream of the dust 
generation system. The diluter thus re- 
duced the dust concentration entering the 
aerosol chamber without varying the oper- 
ating parameters of the f luidized-bed 
generator. The dust concentration could 
be further reduced by feeding a con- 
trolled amount of filtered dilution air 
with the dust-laden air into the aerosol 
chamber. The addition of the dilution 
air, however, increased the total airflow 
rate through the chamber, thereby in- 
creasing the velocity of air past the 
sampling inlets of the instrument being 
tested. 

REFERENCE MEASUREMENTS 

Gravimetric dust samples were collected 
during each test to provide reference 
measurements for comparison to measure- 
ments made by the light-scattering in- 
struments. Five preweighted 37-mm-diam 
polyvinyl chloride (PVC) membrane filters 
in cassettes were connected to the out- 
lets of five cyclones. Chamber air was 
sampled through the cyclones at 2 L/min, 



this flow caused the respirable fraction 
of the dust to be deposited on the pre- 
weighted filters. After sampling, the 
filters were removed and weighed. The 
average respirable dust concentration in 
the chamber during the test period was 
calculated as 

C = M/(F-T), 

where C = concentration, mg/m 3 , 

M = mass of collected dust, mg, 

F 



TABLE 1. - Reference respirable dust 
concentrations ' 



and 



sampling flow rate (0.002 
m 3 /min) , 



T = sampling time, min. 



The calculated values of C for each of 
the five cassette samplers were then 
averaged. The standard deviation for 
each test was also calculated. The co- 
efficient of variation (CV) was then 
calculated by dividing the standard 
deviation by the average concentration 
for each test (table 1). The average 
concentration for each test was then com- 
pared to the time-averaged value indi- 
cated by each of the light-scattering 
monitors during the same test period. 

OTHER DUST MEASUREMENTS 

Several filter samples were collected 
during each test without cyclone precol- 
lectors to provide a measure of the total 
dust concentration 6 in the test chamber 
(table B-l, appendix B). These samples 
were collected at three locations in the 
test chamber, at 2 L/min, with the same 
type filter cassettes as were used for 
collecting the respirable samples. The 
inlets of these filter cassettes were 
faced downward during sampling. The 
ratio of the reference respirable 

6 The term total dust refers to all dust 
particles in the aerosol chamber, both 
respirable size and larger. In essence, 
total dust is all dust collected by the 
filter cassettes without any size- 
selective precollector. 



Test 



Number of 
samples 



Mean, 
mg/m 3 



Standard 
deviation 



ARD 



CV, 
pet 



1 


5 




1.829 


0.194 


10.6 


2 


5 




2.256 


.159 


7.1 


3 


5 




2.241 


.163 


7.2 


4 


4 




.810 


.022 


2.7 


5 


5 




.728 


.044 


6.0 


6 


5 




.348 


.021 


6.0 


7 


5 




3.403 


.319 


9.4 


8 


5 




4.619 


.294 


6.4 


9 


5 




3.532 


.259 


7.3 


10 


5 




4.593 


.334 


7.3 






COAL DUST 






11 


5 




2.459 


0.095 


3.8 


12 


5 




2.073 


.130 


6.3 


13 


4 




2.115 


.054 


2.5 


14 


5 




2.492 


.031 


1.2 


15 


4 




2.555 


.062 


2.4 


16 


5 




2.600 


.035 


1.4 


17 


5 




2.246 


.051 


2.3 


18 


5 




.446 


.020 


4.5 


19 


5 




.393 


.027 


7.0 


20 


5 




.431 


.015 


3.6 


21 


5 




5.517 


.129 


2.3 


22 


5 




5.451 


.151 


2.8 


23 


5 




5.230 


.140 


2.7 



CV 
'As 
sampl 



Coefficent of variat 
measured by gravi 
es. 



ion. 

metric cassette 



dust concentration to the total dust 
concentration provided a crude measure of 
the particle size distribution of the 
test dust in the chamber (table 2). 

Finally, the RAM-1 7 a light-scattering 
dust monitor previously characterized by 
the Bureau (_7 ) , was used to monitor the 
behavior of the dust generator before and 
during each test period. The data 
gathered by this instrument was helpful 
in determining when the dust concentra- 
tion in the chamber had stabilized after 
startup of the dust generating system and 
in detecting unexpected changes in the 
generator output. 

'Reference to specific products does 
not imply endorsement by the Rureau of 
Mines. 



TABLE 2. - Ratios of total dust concentrations to reference respirable 
dust concentrations (T/R) 



Test 



Concentration, mg/ 



Respirable 



Total 2 



T/R 



Test 



Concentration, mg/m 



Respirable 



Total 2 



T/R 



ARD 



COAL DUST 



1, 

2, 
3, 
4, 
5. 
6. 
7. 
8. 
9. 
10. 



1.829 

2.256 

2.241 

.810 

.728 

.348 

3.403 

4.619 

3.532 

4.593 



5.998 

8.121 

NA 

3.307 

1.257 

.743 

10.538 

16.036 

13.959 

15.971 



.28 
.60 
NA 
.08 
.73 
.13 
.10 
.47 
.95 
.48 



11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

table B-l, 



2.459 

2.073 

2.115 

2.492 

2.555 

2.600 

2.246 

.446 

.393 

.431 

5.517 

5.451 

5.230 



5.501 


2.24 


5.799 


2.80 


5.669 


2.68 


6.034 


2.42 


6.516 


2.55 


6.537 


2.51 


5.278 


2.35 


1.155 


2.59 


.877 


2.23 


1.175 


2.73 


9.668 


1.75 


9.954 


1.83 


9.322 


1.78 



NA Not available. 



From table 1. 



"From 



RESULTS AND DISCUSSION 



REFERENCE MEASUREMENTS 

Table 1 lists the respirable dust con- 
centration data used to evaluate the 
light-scattering monitors. In table 1, 
entries under the heading "Mean, mg/ra 3 " 
represent the mean of the reference ves- 
pvvabZe dust concentration measurements 
from the five previously described gravi- 
metric cassette samplers. For ARD, these 
means ranged from 0.35 to 4.62 mg/m with 



.PDS-1 



MDM 



Aerosol chamber 
walls 



Instrument 
table 




Impactor 



Gravimetric total 
dust sampler 



Gravimetric respirable 
dust sampler (cassettes) 



FIGURE 4.— Aerosol chamber, sectional top view. 



CV's between 2.7 and 10.6 pet. Since 
each of the five respirable dust cassette 
samplers was located in a different 
position (fig. 4), the low CV's indicate 
that the ARD was fairly evenly dis- 
tributed in the aerosol chamber. (Table 
B-l, appendix B) lists the total ARD 
reference measurements. 

The respirable coal dust concentration 
data are also listed in table 1. Mean 
coal dust concentrations ranged from 0.39 
to 5.52 mg/m 3 with CV's ranging from 1.1 
to 6.9 pet. Again, dust concentrations 
were fairly uniform in the aerosol cham- 
ber. Table B-l lists the total reference 
coal dust concentrations. 

PDS-1 RESPONSE 

Figure 5 is a plot of the readings from 
each of the three PDS-1 units versus the 
mass concentration of respirable coal 
dust determined gravimetrically for ref- 
erence. (The plotted PDS-1 data are 
listed in appendix C.) The PDS-1 values 
are time-averages of the instrument read- 
ings over the test period. Each corres- 
ponding gravimetric reference value is 
the mean of five measurements determined 
from filter samples taken during the test 
period, as previously described. 




I 2 3 4 5 6 

GRAVIMETRIC RESPIRABLE DUST CONC, mg/m 3 

FIGURE 5.— PDS-1 readings versus gravimetric concentra- 
tions for coal dust. 




I 2 3 4 5 6 

GRAVIMETRIC RESPIRABLE DUST CONC, mg/m 3 

FIGURE 6.— PDS-1 readings versus gravimetric concentra- 
tions for ARD and coal dust. 



Agreement between the readings from 
units A, B, and C was good (fig. 5). 
Regression lines were calculated for each 
unit to fit the equation 

y = Mx, 

where y = PDS-1 reading, mg/m 3 , 

M = slope, 



and 



gravimetric respirable dust 
concentration, mg/m 3 . 



This calculation forced the regression 
line for each unit through the origin. 
The response of each unit to mass concen- 
tration is represented by M. The values 
for M ranged from 2.00 to 2.06, repre- 
senting response variations of only a few 
percent. These results imply that if 
PDS-1 units are calibrated with the ref- 
erence board to the manufacturer's recom- 
mended value, they will agree well with 
each other. 

Figure 6 compares the response of one 
PDS-1 unit with corresponding gravimetric 
values, using both ARD and coal dust. 
(See appendix C, data for unit.) Again, 
each PDS-1 response value represents a 
time-average of the output, and again, 
the reference gravimetric measurement is 
the mean of five measurements. The PDS-1 
response to ARD was significantly 



different than the PDS-1 response to 
coal. The M value was 0.59 for ARD, as 
opposed to 2.06 for coal dust. These 
data imply that the response of the PDS-1 
depends significantly on characteristics 
of dust particles other than mass, such 
as size and index of refraction, as is 
the case for other instruments based on 
light-scattering (_5, 7^). Nevertheless, 
for a particular dust, the response was 
linear with mass concentration over the 
ranged tested. For both coal and ARD, 
the coefficient of determination (r ) was 
greater than 0.9 when the data were 
fitted to the equation y = M/x. 

PCD-1 RESPONSE 

Since only one PCD-1 unit was available 
for testing, inter-unit comparison was 
not possible. 

Figure 7 shows the response of the PCD- 
1 versus corresponding gravimetric 
values, for both ARD and coal dust. (See 
appendix C for the PCD-1 data. ) Again, 
the response to ARD was different than 
the response to coal dust. The values of 
M were 0.22 for ARD and 0.16 for coal 
dust. Again, the response was linear 
with mass concentration for each dust. 
The slopes (M) of these responses could 
have been changed by entering a "K fac- 
tor" into the PCD-1 's microprocessor. 
For these tests the "K factor" was kept 




I 2 3 4 5 6 

GRAVIMETRIC RESPIRABLE DUST CONC, mg/m 3 

FIGURE 7.— PCD-1 readings versus gravimetric dust con- 
centrations for ARD and coal dust. 



at unity. The value of r was 0.84 for 
ARD and 0.97 for coal dust. For the PCD- 
1, the slopes of the curves show the re- 
sponse to ARD was greater than the re- 
sponse to coal. For the PDS-1, the 
situation was reversed. 



EFFECT OF PARTICLE SIZE DISTRIBUTIONS 

In the absence of impactor data, ratios 
of total to respirable dust concentration 
measurements (T/R) provided some indica- 
tion of the particle size distribution. 
Table 2 shows the T/R ratios for both the 
ARD and coal dust tests. 

Some variability existed in the size 
distribution, as indicated by the T/R 
ratios. Variability also existed in the 
responses of the light-scattering instru- 
ments, as indicated by the ratios of the 
PDS-1 and PCD-1 readings to the gravi- 
metric determinations of mass concentra- 
tion (M). Nevertheless, no statistically 
significant correlation could be found 
between changes in particle size distri- 
bution and the responses of the instru- 
ments. Theoretically, particle size can 
have an effect on the response of 
light-scattering instruments. More 
careful measurement and control of par- 
ticle size distributions during similar 
tests would be needed to confirm size 
dependence. 



CONCLUSIONS 



Both the PDS-1 and the PCD-1 responded 
linearly with mass concentration for 
both ARD and coal dust over the range 



of about 0.3 to 5 mg/m 3 . 



However, 



the instruments' responses to ARD and 
coal dust were different. The PCD-1 's 
response to ARD was greater then 
its response to the coal dust. The 
situation was reversed for the PDS-1. 
The major difference between the two 
instruments is that the PCD-1 draws 
air into its light-sensor chamber 



with an air pump, whereas the PDS-1 has 
no air pump. 

As is the case with 
scattering dust monitors, 
pends on characteristics 
particles other than mass, 
response differences observed using ARD 
and coal dust probably resulted from dif- 
ferences in the indexes of refraction of 
these two dusts. However, this could not 
be determined by the data collected dur- 
ing these tests. 



many light- 
response de- 
of the dust 

The apparent 



REFERENCES 



1. U.S. Code of Federal Regulations. 
Title 30 — Mineral Resources; Chapter I — 
Mine Safety and Health Admin. , Department 
of Labor; Subchapter — Coal Mine Safety 
and Health; Part 70 — Mandatory Health 
Standards — Underground Coal Mines, Sec. 
70.100 (a); July 1, 1985. 

2. U.S. Bureau of Mines. Instantan- 
eous Sampling Improves Longwall Dust Con- 
trol. Technol. News 134, Feb. 1982, 2 pp. 



3. Lilienfeld, P. Improved Light 
Scattering Dust Monitor (contract 
HO377092, GCA Corp.). BuMines OFR 90-79, 
1979, 48 pp.; NTIS PB 299 938/AS. 

4. Lilienfeld, P., and R. Stern. Per- 
sonal Dust Monitor — Light Scattering 
(contract HO308132, GCA Corp.). BuMines 
OFR 95-83, 1982, 40 pp.; NTIS PB 
83-205435. 



10 



5. Marple, V. A., and K. L. Rubow. 
Respirable Dust Measurement (contract 
J01 13042, Univ. Mn.). BuMines OFR 92-85, 
1984, 154 pp.; NTIS PB 85-245843/AS. 

6. . An Aerosol Chamber for In- 
strument Evaluation and Calibration. Am. 



Ind. Hyg. Assoc. J., v. 44, May 1983, 
pp. 361-367. 

7. Williams, K. L. , and R. J. Timko. 
Performance Evaluation of a Real-Time 
Aerosol Monitor. BuMines IC 8968, 1984, 
20 pp. 






11 



APPENDIX A.— MANUFACTURER'S SPECIFICATIONS 



Range: 

Sensitivity: 
Particle size range: 
Calibration: 
Power source: 
Operating time: 
Dimensions: 
Weight: 



PDS-1 Personal Dust Sensor 

0.01 to 10 mg/m 3 or 0.1 to 100 mg/m 3 

0.01 mg/m 3 

0.01 to 10 pm 

Built-in reference board 

Rechargeable Ni-Cd batteries 

9 h 

4-3/8 by 3-1/2 by 1-1/2 in 

1 lb 7 oz 



MDM-1 Mini Dosimeter 



Input range: 

Resolution: 

Precision: 

Data acquisition: 

Display: 

Data output: 

Power source: 

Operating time: 

Dimensions: 

Weight: 



Range: 

Sensitivity: 
Particle size range: 
Power source: 
Operating time: 
Dimensions: 
Weight: 



to 1000 mV 

1 mV 

±0.5 pet full scale 

180 data points per min; stores 800 1-min averages 

3-1/2-digit mass concentration from to 10.00 mg/m 3 

Serial (ASCII) TTL level 

Rechargeable Ni-Cd batteries 

12 h 

3-3/8 by 1-3/4 by 6-1/8 in 

10 oz 

PCD-1 Digital Dust Indicator 

0.001 to 9.999 mg/m 3 
0.001 mg/m 3 
0.01 to 10.00 pm 
Rechargeable Ni-Cd batteries 

10 h 

11 by 3-1/2 by 5-3/4 in 
8 lb 



12 



APPENDIX B. — TOTAL DUST CONCENTRATIONS 



Table B-l lists the means of several 
total ARD and coal dust concentration 
measurements. The means for ARD ranged 
from 0.743 to 16.036 me/m 3 with CV's 



to 16.036 mg/m J , with 

TABLE B-l. - Total dust concentrations 



ranging from 0.6 and 9.3 pet. The coal 
dust means ranged from 0.877 to 9.954 
mg/m 3 , with CV's ranging from 1.0 and 
13.2 pet. 



Test 


Number of 


Mean, 


Standard 


rev, 


Test 


Number of 


Mean, 


Standard 


CV, 




samples 


mg/m 3 


deviation 


pet 




samples 


mg/m 3 


deviation 


pet 




ARD 








COAL DUST 






1 


1 


5.998 


NAp 


NAp 


11 


3 


5.501 


0.221 


4.0 


2 


1 


8.121 


NAp 


NAp 


12 


3 


5.799 


.559 


9.6 


3 





2 NA 


NAp 


NAp 


13 


3 


5.669 


.122 


2.1 


4 


3 


3.307 


0.309 


9.3 


14 


3 


6.034 


.059 


1.0 


5 


3 


1.257 


.063 


5.0 


15 


3 


6.516 


.399 


6.1 


6 


3 


.743 


.027 


3.6 


16 


3 


6.537 


.405 


6.2 


7 


3 


10.538 


.424 


4.0 


17 


3 


5.278 


.694 


13.2 


8 


3 


16.036 


1.333 


8.3 


18 


3 


1.155 


.046 


4.0 


9 


3 


13.959 


.715 


5.1 


19 


3 


.877 


.031 


3.5 


10 


3 


15.971 


.094 


.6 


20 


3 


1.175 


.062 


5.3 












21 


3 


9.668 


.641 


6.6 














3 


9.954 


.654 


6.6 












23 


3 


9.322 


.504 


5.4 



NAp Not applicable. 'As measured by gravimetric cassette samplers. 2 Lost sample. 



APPENDIX C.~ PDS-1 AND PCD-1 TEST DATA 



(Milligrams per cubic meter) 



13 



Test 


PDS-1 


PCD-1 


Test 


PDS-1 


PCD-1 




Unit A 


Unit B 


Unit C 


Unit A | Unit B 


Unit C 




ARD 




COAL DUST 






1 


] NA 


NA 


0.740 


0.489 




4.661 


3.982 


3.520 


0.265 




1.695 


NA 


1.271 


.609 


12 


3.959 


3.353 


2.872 


.214 




NA 


1.392 


1.560 


NA 


13 


2.410 


3.407 


3.485 


NA 


4 


NA 


.521 


.526 


.232 


14 


4.370 


4.759 


4.649 


NA 


5 


NA 


.658 


.749 


.321 


15 


6.092 


4.945 


4.833 


NA 




NA 


NA 


.343 


.094 


16 


4.074 


4.866 


4.998 


.396 


7 


NA 


NA 


2.037 


.487 




3.862 


4.307 


NA 


.373 


8 


NA 


NA 


3.053 


NA 


18 


.582 


.584 


.622 


NA 


9 


5.028 


2.341 


2.034 


.942 




.460 


.471 


.522 


.072 




NA 


4.348 


2.321 


1.010 


20 


.629 


.692 


.735 


.105 












21 


10.604 


10.887 


11.127 


.883 














13.674 


12.153 


12.670 


.870 












23 


9.681 


12.035 


11.931 


.851 



Data not available because of malfunction of dust monitor. 



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Bureau of Mines— Prod, and Distr. 
Cochrans Mill Road 
P.O. Box 18070 
Pittsburgh. Pa. 15236 



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